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TRIGGER FINGER

Introduction

Trigger finger, or stenosing tendovaginitis, occurs when the flexor tendons cannot pass through the A-1 pulley smoothly.  Whether the pulley thickens, the tenosynovium thickens and/or the tendons deform and develop a "nodule," the result is the same: loss of smooth active flexion and extension in the digit. The digit can lock in flexion or extension or simply be difficult to move without significant pain.

Related Anatomy

  • Caused by anomalous anatomy, including abnormal lumbrical insertion and/or proximal decussation of flexor digitorum sublimis (FDS) tendon
  • Narrowing/thickening of FDS tendon sheath at the A1 pulley level
  • Histology shows non-inflammatory fibrosis; occasionally, chronic inflammatory cells are present

Relevant Basic Science

  • When tendon sheath becomes edematous, the sheath becomes fibrotic and may undergo cartilaginous metaplasia; the tendon becomes thinner under the area of constriction and thickens proximal to the constriction. The swollen portion of the tendon is referred to as a nodule or "Notta's Node".

Incidence and Related Conditions

  • More common in women (2-6 times); pregnancy is a predisposing risk factor
  • Predisposing systemic conditions: rheumatoid arthritis, diabetes, gout, amyloidosis, mucopolysaccharidoses
  • Often comorbid with de Quervain’s disease, carpal tunnel syndrome, and elbow tendinopathy
  • Repetitive trauma likely plays a central but not sole role in the etiology of the condition

Differential Diagnosis

  • de Quervain’s disease
  • Dupuytren’s contracture
  • Metaphalangeal (MP) joint loose body/dislocation
  • Proximal interphalangeal (PIP) joint dislocation
  • Volar plate avulsion with entrapment
  • Tendon sheath tumor
  • Intrinsic tendon injury on an irregular metacarpal head
  • Rheumatoid arthritis
Clinical Presentation Photos and Related Diagrams
  • Trigger Finger (Hover over right edge to see more images)
    Trigger Finger Locked (Hover over right edge to see more images)
  • Right Long Trigger Finger Exam
    Right Long Trigger Finger Exam - Examiner is palpating A-1 pulley while passively flexing and exending the finger. Palpation should reveal tenderness and/or cripitus as the flexor tendon moves through the A-1 pulley.
Symptoms
Pain at the base of the finger at the distal palmar crease superficial to the MP joint.
Painful clicking, snapping, catching, triggering or temporary locking of the finger with motion
Lump, nodule or crepitus (crutching) under the distal palmar crease at the base of the finger
Limited painful finger range of motion
Flexion or extension contracture due to a permanent partially locked trigger finger
Typical History

A patient often notices a click in his or her finger that eventually becomes painful, and the patient may be unable to fully flex the finger. In chronic cases, the trigger finger may become locked, resulting in fixed-joint contracture

Positive Tests, Exams or Signs
Tenderness
Trigger Finger
Flexor Tendon Exam
Range of Motion: Active
Work-up Options
Sonographic studies - Ultrasound
Magnetic resonance imaging - MRI without contrast
Radiology studies - X-ray
Images (X-Ray, MRI, etc.)
  • X-ray Normal in Trigger Fingers. P1=Proximal Phalanx; P2=Middle Phalanx; P3=Distal Phalanx
    X-ray Normal in Trigger Fingers. P1=Proximal Phalanx; P2=Middle Phalanx; P3=Distal Phalanx
Treatment Options
Conservative: 
  • Activity modification
  • Splinting
  • NSAIDS
  • Corticosteroid injections
Operative: 
  • Percutaneous release of A1 pulley
  • Open release or excision of the A1 pulley
Treatment Photos and Diagrams
  • Trigger finger with small Dupuytren's cord superficial to A-1 pulley. (Hover over right edge to see more images)
    Trigger finger with small Dupuytren's cord superficial to A-1 pulley. (Hover over right edge to see more images)
  • Transverse incision for releasing index and long trigger fingers. Longitudinal incisions and also be used.
    Transverse incision for releasing index and long trigger fingers. Longitudinal incisions and also be used.
  • Blunt dissection used to expose A-1 pulley.
    Blunt dissection used to expose A-1 pulley.
  • Edge os A-1 exposed. Second arrow at fiber of palmar aponeurotic pulley(superficial inter metacarpal ligaments).
    Edge os A-1 exposed. Second arrow at fiber of palmar aponeurotic pulley(superficial inter metacarpal ligaments).
  • A-1 pulley exposed and neurovascular bundle visible.
    A-1 pulley exposed and neurovascular bundle visible.
  • Probe pulling FDS. Note erosions on FDS and tenosynovium evading tendon substance. PIP joint passively flexing after A-1 release.
    Probe pulling FDS. Note erosions on FDS and tenosynovium evading tendon substance. PIP joint passively flexing after A-1 release.
  • Tensynovium between FDS and FDP which sometimes thickens and requires excision to fully relieve catching and locking with active motion.
    Tensynovium between FDS and FDP which sometimes thickens and requires excision to fully relieve catching and locking with active motion.
  • Before closure active motion under local and sedation checking to verify complete release, no locking and full active range of motion.
    Before closure active motion under local and sedation checking to verify complete release, no locking and full active range of motion.
  • Transverse incision used to release index and long trigger fingers closed with simple sutures.
    Transverse incision used to release index and long trigger fingers closed with simple sutures.
Complications
  • Corticosteriod injections help trigger fingers 60% of the time with a 60% recurrence rate at one year. Steriod injection failure increases in young patients, diabetic patients and those with multiple triggers.
  • Operative: infection, secondary adherence, scar tenderness, mild PIP joint contractures, neurovascular bundle injuries, ulnar drift of digit, flexor tendon bowstringing
Outcomes
  • Splinting reportly can eliminated triggering in 66% of patients after 1 year
  • Steroid injection: success in 40-90% of patients but recurrence common
  • A1 pulley release: elimination of triggering in >90% of patients
Video
Trigger Finger
Chronic Right Long and Ring Finger Triggering
Ultrasound of normal flexor tendon at A-1 pulley area. Metacarpal Cortex (M); Volar Plate (VP); Proximal Phalanx Cortex (PP)
Key Educational Points
  • The pathologic mechanism of acquired trigger finger is characterized by fibrocartilage metaplasia. There is no synovial layer on the A-1 jpulley.
  • In trigger finger, the digits are affected in the following decreasing order of prevalence: thumb, ring, long, little, index.
  • Of patients with trigger finger who do not have diabetes, 65% to 90% obtain relief of symptoms with one or two injections. In patients with diabetes, relief of symptoms after injection is less successful.
Practice and CME
References

New Articles

  1. Degreef I, Devlieger B, De Smet L. Primary ulnar superficial slip resection in complicated trigger finger. J Plast Surg Hand Surg 2014;48(5):340-3.
  2. Yang TH, Chen HC, Liu YC, et al. Clinical and pathological correlates of severity classifications in trigger fingers based on computer-aided image analysis.Biomed Eng Online 2014 ePub.
  3. Wolfe SW. Tendinopathy.  In: Wolfe SW, Hotchkiss RN, Pederson WC, Kozin SH,  eds. Green’s Operative Hand Surgery, sixth edition.  Philadelphia: Elsevier/Churchill Livingstone 2011;62:2071-2079.

Reviews

  1. Vargas A, Chiapas-Gasca K, Hernández-Díaz C, et al. Clinical anatomy of the hand. Reumatol Clin 2012;8(S2):25-32.
  2. Akhtar S, Bradley MJ, Quinton DN, Burke FD. Management and referral for trigger finger/thumb. BMJ 2005;331(7507):30-3.

Classics

  1. Notta A. Recherches sur une affection particuliere des gaines tendineuses de la main, caracterisee par le development d’une nodosite sur le trajet des tendons fleschisseurs des doigts et par l’empechement de leurs mouvements. Arch Gen Med 1850;24:142-61.
  2. Hueston JT, Wilson WF. The aetiology of trigger finger explained on the basis of intratendinous architecture. Hand 1972 Oct;4(3):257-60.
  3. Fahey JJ, Bollinger JA. Trigger-finger in adults and children. J Bone Joint Surg Am 1954 Dec;36(6):1200-18.
  4. Sampson SP, Badalamente MA, Hurst LC, Seidman J. Pathobiology of the human trigger finger. J Hand Surg 1991;16A:714-21.